The Q Wave in Precordial Electrocardiograms Overlying the Hypertrophied Right Ventricle: Intracavity Leads

Right ventricular cavity electrocardiograms were obtained in six subjects having qR patterns in V leads made from precordial sites overlying the hypertrophied right ventricle. Four of the six, unlike control subjects, had no initial R wave in the right ventricular cavity; one had only a questionable initial R wave. Simultaneous intracavity and precordial electrocardiograms suggested that the initial Q wave over the hypertrophied right ventricle is due to abnormal depolarization of the interventricular septum, and that the large R wave over the hypertrophied right ventricle is the result of delay in activation of the free wall of that chamber.